Ingestion and retention of microplastics by corals and sponges

This study reveals more than 1000-fold variation in microplastic ingestion among different benthic filter-feeding genera that are abundant on coral reefs. Overall, genera with larger polyp sizes (e.g. Dipsastrea) ingested more microbeads per unit tissue area than genera with small polyps (e.g. Acropora). Microbeads were observed adhering to the external surfaces of corals and sponges, and were also ingested into the polyp cavity of hard and soft corals, and into the internal canals and chambers of sponges. After ingestion, microbeads were retained for up to 14 days although retention was variable both within- and among-genera. Finally, we observed greater ingestion of small and/or medium sized microbeads (27 – 75 µm diameter) compared with large microbeads (300 - 1000 µm diameter) for all six hard coral genera examined, but greater ingestion of medium (45 - 53 µm diameter) than small microbeads (27 - 32 µm diameter) for the two sponge genera and the soft coral Lobophytum.

Software/equipment used to create/collect the data: Aquarium-based experiments conducted at Orpheus Island Research Station and Marine Aquaculture Research Facility at James Cook University. Laboratory analysis of samples involving tissue analyses and microscopy. Histology methods to section coral tissues.

Software/equipment used to manipulate/analyse the data: Data were analysed in R